docs: def _fact_to_tuple(self, fact):
          """
          Convert a ``Fact`` to its normalized tuple.
  
          This is where all type conversion for ``Fact`` attributes to strings as
          well as any normalization happens.
  
          Note:
              Because different writers may require different types, we need to
              do this individually.
  
          Args:
              fact (hamster_lib.Fact): Fact to be converted.
  
          Returns:
              FactTuple: Tuple representing the original ``Fact``.
          """
          # Fields that may have ``None`` value will be represented by ''
          if fact.category:
              category = fact.category.name
          else:
              category = ''
  
          description = fact.description or ''
  
          return FactTuple(
              start=fact.start.strftime(self.datetime_format),
              end=fact.end.strftime(self.datetime_format),
              activity=text_type(fact.activity.name),
              duration=fact.get_string_delta(format='%M'),
              category=text_type(category),
              description=text_type(description),
          )